1,051 research outputs found

    Automated Placement Of A Transistor Pair For Analogue

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    The performances of analogue circuits are affected by surrounding parameters such as levels of noise, thermal gradients of a circuit, and parasitic effects from both resistive and capacitive part. As there are no effective approaches to handle these analogue constraints as mentioned above, the focuses to develop IC design tools are bended towards digital circuits. The purpose of this research is to introduce a complete methodology for transistor pair placement for analogue layout using a concept of cells and arrays based on migration and reuse. The entire process consists of Standard Cell Generation to produce standard cell for analogue circuits, Matching Generator with array alignment to generate transistor matching of common-centroid arrangement, and Auto Routing for global routing. The methodology is translated into automation by a graphical user interface to render a fully functional layout designs in a few steps and fraction of time. This research describes such a system in obtaining a layout that can be configured like a set of building blocks that meets all design specifications. In comparison to all the different approaches that have been discussed and analysed prior to this research, a new design flow for analogue layout combined with automation is constructed by considering transistor matching as a constraint

    Analog layout design automation: ILP-based analog routers

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    The shrinking design window and high parasitic sensitivity in the advanced technology have imposed special challenges on the analog and radio frequency (RF) integrated circuit design. In this thesis, we propose a new methodology to address such a deficiency based on integer linear programming (ILP) but without compromising the capability of handling any special constraints for the analog routing problems. Distinct from the conventional methods, our algorithm utilizes adaptive resolutions for various routing regions. For a more congested region, a routing grid with higher resolution is employed, whereas a lower-resolution grid is adopted to a less crowded routing region. Moreover, we strengthen its speciality in handling interconnect width control so as to route the electrical nets based on analog constraints while considering proper interconnect width to address the acute interconnect parasitics, mismatch minimization, and electromigration effects simultaneously. In addition, to tackle the performance degradation due to layout dependent effects (LDEs) and take advantage of optical proximity correction (OPC) for resolution enhancement of subwavelength lithography, in this thesis we have also proposed an innovative LDE-aware analog layout migration scheme, which is equipped with our special routing methodology. The LDE constraints are first identified with aid of a special sensitivity analysis and then satisfied during the layout migration process. Afterwards the electrical nets are routed by an extended OPC-inclusive ILP-based analog router to improve the final layout image fidelity while the routability and analog constraints are respected in the meantime. The experimental results demonstrate the effectiveness and efficiency of our proposed methods in terms of both circuit performance and image quality compared to the previous works

    Layoutautomatisierung im analogen IC-Entwurf mit formalisiertem und nicht-formalisiertem Expertenwissen

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    After more than three decades of electronic design automation, most layouts for analog integrated circuits are still handcrafted in a laborious manual fashion today. Obverse to the highly automated synthesis tools in the digital domain (coping with the quantitative difficulty of packing more and more components onto a single chip – a desire well known as More Moore), analog layout automation struggles with the many diverse and heavily correlated functional requirements that turn the analog design problem into a More than Moore challenge. Facing this qualitative complexity, seasoned layout engineers rely on their comprehensive expert knowledge to consider all design constraints that uncompromisingly need to be satisfied. This usually involves both formally specified and nonformally communicated pieces of expert knowledge, which entails an explicit and implicit consideration of design constraints, respectively. Existing automation approaches can be basically divided into optimization algorithms (where constraint consideration occurs explicitly) and procedural generators (where constraints can only be taken into account implicitly). As investigated in this thesis, these two automation strategies follow two fundamentally different paradigms denoted as top-down automation and bottom-up automation. The major trait of top-down automation is that it requires a thorough formalization of the problem to enable a self-intelligent solution finding, whereas a bottom-up automatism –controlled by parameters– merely reproduces solutions that have been preconceived by a layout expert in advance. Since the strengths of one paradigm may compensate the weaknesses of the other, it is assumed that a combination of both paradigms –called bottom-up meets top-down– has much more potential to tackle the analog design problem in its entirety than either optimization-based or generator-based approaches alone. Against this background, the thesis at hand presents Self-organized Wiring and Arrangement of Responsive Modules (SWARM), an interdisciplinary methodology addressing the design problem with a decentralized multi-agent system. Its basic principle, similar to the roundup of a sheep herd, is to let responsive mobile layout modules (implemented as context-aware procedural generators) interact with each other inside a user-defined layout zone. Each module is allowed to autonomously move, rotate and deform itself, while a supervising control organ successively tightens the layout zone to steer the interaction towards increasingly compact (and constraint compliant) layout arrangements. Considering various principles of self-organization and incorporating ideas from existing decentralized systems, SWARM is able to evoke the phenomenon of emergence: although each module only has a limited viewpoint and selfishly pursues its personal objectives, remarkable overall solutions can emerge on the global scale. Several examples exhibit this emergent behavior in SWARM, and it is particularly interesting that even optimal solutions can arise from the module interaction. Further examples demonstrate SWARM’s suitability for floorplanning purposes and its application to practical place-and-route problems. The latter illustrates how the interacting modules take care of their respective design requirements implicitly (i.e., bottom-up) while simultaneously paying respect to high level constraints (such as the layout outline imposed top-down by the supervising control organ). Experimental results show that SWARM can outperform optimization algorithms and procedural generators both in terms of layout quality and design productivity. From an academic point of view, SWARM’s grand achievement is to tap fertile virgin soil for future works on novel bottom-up meets top-down automatisms. These may one day be the key to close the automation gap in analog layout design.Nach mehr als drei Jahrzehnten Entwurfsautomatisierung werden die meisten Layouts für analoge integrierte Schaltkreise heute immer noch in aufwändiger Handarbeit entworfen. Gegenüber den hochautomatisierten Synthesewerkzeugen im Digitalbereich (die sich mit dem quantitativen Problem auseinandersetzen, mehr und mehr Komponenten auf einem einzelnen Chip unterzubringen – bestens bekannt als More Moore) kämpft die analoge Layoutautomatisierung mit den vielen verschiedenen und stark korrelierten funktionalen Anforderungen, die das analoge Entwurfsproblem zu einer More than Moore Herausforderung machen. Angesichts dieser qualitativen Komplexität bedarf es des umfassenden Expertenwissens erfahrener Layouter um sämtliche Entwurfsconstraints, die zwingend eingehalten werden müssen, zu berücksichtigen. Meist beinhaltet dies formal spezifiziertes als auch nicht-formal übermitteltes Expertenwissen, was eine explizite bzw. implizite Constraint Berücksichtigung nach sich zieht. Existierende Automatisierungsansätze können grundsätzlich unterteilt werden in Optimierungsalgorithmen (wo die Constraint Berücksichtigung explizit erfolgt) und prozedurale Generatoren (die Constraints nur implizit berücksichtigen können). Wie in dieser Arbeit eruiert wird, folgen diese beiden Automatisierungsstrategien zwei grundlegend unterschiedlichen Paradigmen, bezeichnet als top-down Automatisierung und bottom-up Automatisierung. Wesentliches Merkmal der top-down Automatisierung ist die Notwendigkeit einer umfassenden Problemformalisierung um eine eigenintelligente Lösungsfindung zu ermöglichen, während ein bottom-up Automatismus –parametergesteuert– lediglich Lösungen reproduziert, die vorab von einem Layoutexperten vorgedacht wurden. Da die Stärken des einen Paradigmas die Schwächen des anderen ausgleichen können, ist anzunehmen, dass eine Kombination beider Paradigmen –genannt bottom-up meets top down– weitaus mehr Potenzial hat, das analoge Entwurfsproblem in seiner Gesamtheit zu lösen als optimierungsbasierte oder generatorbasierte Ansätze für sich allein. Vor diesem Hintergrund stellt die vorliegende Arbeit Self-organized Wiring and Arrangement of Responsive Modules (SWARM) vor, eine interdisziplinäre Methodik, die das Entwurfsproblem mit einem dezentralisierten Multi-Agenten-System angeht. Das Grundprinzip besteht darin, ähnlich dem Zusammentreiben einer Schafherde, reaktionsfähige mobile Layoutmodule (realisiert als kontextbewusste prozedurale Generatoren) in einer benutzerdefinierten Layoutzone interagieren zu lassen. Jedes Modul darf sich selbständig bewegen, drehen und verformen, wobei ein übergeordnetes Kontrollorgan die Zone schrittweise verkleinert, um die Interaktion auf zunehmend kompakte (und constraintkonforme) Layoutanordnungen hinzulenken. Durch die Berücksichtigung diverser Selbstorganisationsgrundsätze und die Einarbeitung von Ideen bestehender dezentralisierter Systeme ist SWARM in der Lage, das Phänomen der Emergenz hervorzurufen: obwohl jedes Modul nur eine begrenzte Sichtweise hat und egoistisch seine eigenen Ziele verfolgt, können sich auf globaler Ebene bemerkenswerte Gesamtlösungen herausbilden. Mehrere Beispiele veranschaulichen dieses emergente Verhalten in SWARM, wobei besonders interessant ist, dass sogar optimale Lösungen aus der Modulinteraktion entstehen können. Weitere Beispiele demonstrieren SWARMs Eignung zwecks Floorplanning sowie die Anwendung auf praktische Place-and-Route Probleme. Letzteres verdeutlicht, wie die interagierenden Module ihre jeweiligen Entwurfsanforderungen implizit (also: bottom-up) beachten, während sie gleichzeitig High-Level-Constraints berücksichtigen (z.B. die Layoutkontur, die top-down vom übergeordneten Kontrollorgan auferlegt wird). Experimentelle Ergebnisse zeigen, dass Optimierungsalgorithmen und prozedurale Generatoren von SWARM sowohl bezüglich Layoutqualität als auch Entwurfsproduktivität übertroffen werden können. Aus akademischer Sicht besteht SWARMs große Errungenschaft in der Erschließung fruchtbaren Neulands für zukünftige Arbeiten an neuartigen bottom-up meets top-down Automatismen. Diese könnten eines Tages der Schlüssel sein, um die Automatisierungslücke im analogen Layoutentwurf zu schließen

    Dynamic Comparator, SR Latch and Bootstrap Switch for 10 Bits SAR ADC for Biomedical Applications

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    This document presents the design of a Dynamic Comparator, a SR Latch and a Sample and Hold circuit for a 10 bits SAR ADC. Designs are performed using TSMC 0.18 um CMOS technology with 1.8 V supply voltage. The Dynamic comparator with Strong Arm topology is chosen to fulfill the requirements of SAR ADC. Its performance is tested at simulation level with a clock frequency of 10 KHz to 310 MHz, using typical parameter of process, nominal supply voltage and room temperature. Although, results are presented only at clock frequency of 100 KHz. This analysis showed that comparator has an input offset of 17.8 mV and power consumption of 36.27 nW. Power consumption is in the power budget of SAR ADC however, the input offset voltage has limited the resolution of SAR ADC. The SR latch is designed at transistor level using NAND gates. The circuit has additional digital logic and an external reset pin in order to avoid the prohibited condition. After implementing this modification, it shows a correct functionality at a clock frequency of 100 KHz. The sample and hold circuit is designed with a bootstrap switch for a load capacitance of 300 pF which is the total capacitance of the circuit when it is integrated to the SAR ADC.ITESO, A. C

    A Pre-Search Assisted ILP Approach to Analog Integrated Circuit Routing

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    The routing of analog integrated circuits (IC) has long been a challenge due to numerous constraints (such as symmetry and topology-matching) that matter for overall circuit performance. Existing automatic analog IC routing algorithms can be broadly categorized into two approaches: sequential approach that heuristically routes one net after another and constructive ILP (Integer Linear Programming). The former approach is usually fast but may miss opportunities of finding good solutions. The constructive ILP provides optimal solutions but can be very time consuming. We propose a simple yet efficient method that combines the advantages of both existing approaches. First, sequential routing is performed to obtain a set of candidate routing paths for each net. Then, an ILP is applied to commit each net to only one of its candidate routes. Experiments on two op-amp designs show that the post-layout performance (such as gain and phase margin) from our method is close to that of manual design. Our method also outperforms a previous work of automated analog IC routing

    Placement techniques in automatic analog layout generation.

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    模擬電路版圖設計是一個非常複雜和耗時的過程。通常情況下,設計一個高質量的模擬電路版圖需要電子工程師花費幾週甚至更長的時間。模擬電路的電子特性對於電路的細節設計非常敏感,因此,減小電路中的失配現象成為模擬電路版圖設計中一個非常重要的課題。在本論文中,我們提出了一系列實際的佈局技術,來降低電路的失配並提高繞線的成功率。我們可以非常容易的將這些技術整合至一個完整的模擬佈局和佈線的工具中,此工具可以在幾分鐘內生成一個完整的、高質量的模擬電路版圖。同時,該版圖能夠通過設計規則驗證(DRC)和佈局與電路設計一致性檢測(LVS)。模擬結果顯示,它的電路性能能夠與達到甚至超出手工設計的電路版圖。我們的論文主要作出了以下兩方面貢獻。1. 平衡佈局:對於模擬電路中的電子元器件,如電容、電阻、晶體管等進行一維和二維的平衡佈局。電子工程師可以根據不同的設計需求,通過選擇不同的佈局參數來改變電路的佈局排列方式。同時,在模擬退火算法中,我們著重考慮了器件間的匹配以生成高質量的模擬電路佈局。2. 消除阻塞的電路佈局:在模擬電路設計中,我們期望盡量避免在電子元器件密度較高的區域進行繞線。因此,我們需要在電路佈局設計過程中在電子元器件間留有足夠的佈線空間。為達到這個目標,我們提出了更精確的阻塞估計方法和版圖拓展方法,使其能夠生成一個高質量、高繞線成功率的電路佈局結果。為了驗證生成的電路版圖的質量和匹配特性,我們利用蒙地卡羅方法來模擬電路中的製程偏差和失配特性。實驗結果顯示,我們的工具可以在幾分鐘內自動生成高質量的電路版圖,與人工設計通常需要花費數日至數週相比,設計時間大幅縮短,同時電路的匹配特性得以提升。Analog layout design is a complicated and time-consuming process. It often takes couples of weeks for the layout designers to generate a qualied layout. The elec-trical properties of analog circuit are very sensitive to the layout details, and mis-match reduction becomes a very important issue in analog layout design.In this thesis, we will present some practical placement techniques to reduce mismatch and improve routability. These techniques can be easily integrated into a complete analog placement and routing ow, which can produce in just a few min-utes a complete and high quality layout for analog circuits that passes the design rule check, layout-schematic check and with performance veried by simulations. The contents of this thesis will focus on the following two issues:(1) Symmetry Placement: We consider symmetric placement of transistors, re-sistors and capacitors, which includes 1-D symmetry and 2-D symmetry (or called common centroid). Different symmetric placement congurations, derived accord-ing to the practical needs in analog design, are considered for the matching devices in the simulated annealing engine of the placer in order to generate a placement with high quality.(2) Congestion-driven Placement: In analog design, wires are preferred not be routed over active devices, so we need to leave enough spaces properly for routing between the devices during the placement process. To achieve this, we explore congestion estimation and layout expansion during the placement step in order to produce a good and routable solution.In order to verify the quality of the generated layouts in terms of mismatch, we will run Monte Carlo simulations on them with variations in process and mismatch. Experiments show that our methodology can generate high quality layout automatically in just a few minutes while manual design may take couples of days.Detailed summary in vernacular field only.Detailed summary in vernacular field only.Detailed summary in vernacular field only.Detailed summary in vernacular field only.Detailed summary in vernacular field only.Cui, Guxin.Thesis (M.Phil.)--Chinese University of Hong Kong, 2012.Abstracts also in Chinese.Abstract --- p.iAcknowledgement --- p.ivChapter 1 --- Introduction --- p.1Chapter 1.1 --- Background --- p.1Chapter 1.2 --- Physical Design --- p.2Chapter 1.3 --- Analog Placement --- p.4Chapter 1.3.1 --- Methodologies of Analog Placement --- p.4Chapter 1.3.2 --- Symmetry Constraints of Analog Placement --- p.5Chapter 1.4 --- Process Variation and Layout Mismatch --- p.6Chapter 1.4.1 --- Process Variation --- p.6Chapter 1.4.2 --- Random Mismatch and Systematic Mismatch --- p.7Chapter 1.5 --- Monte Carlo Simulation Procedure --- p.9Chapter 1.6 --- Problem Formulation of Placement --- p.9Chapter 1.7 --- Motivations --- p.10Chapter 1.8 --- Contributions --- p.11Chapter 1.9 --- Thesis Organization --- p.12Chapter 2 --- Literature Review on Analog Placement --- p.13Chapter 2.1 --- Topological Representations Handling Symmetry Constraints --- p.14Chapter 2.1.1 --- Symmetry within the Sequence-Pair (SP) Representation . --- p.14Chapter 2.1.2 --- Block Placement with Symmetry Constraints Based on the O-Tree Non-Slicing Representation --- p.16Chapter 2.1.3 --- Placement with Symmetry Constraints for Analog Layout Design Using TCG-S --- p.17Chapter 2.1.4 --- Modeling Non-Slicing Floorplans with Binary Trees --- p.19Chapter 2.1.5 --- Segment Trees Handle Symmetry Constraints --- p.20Chapter 2.1.6 --- Center-based Corner Block List --- p.22Chapter 2.2 --- Other Works on Analog Placement Constraints --- p.25Chapter 2.2.1 --- Deterministic Analog Placement with Hierarchically Bounded Enumeration and Enhanced Shape Functions --- p.25Chapter 2.2.2 --- Analog Placement Based on Symmetry-Island Formulation --- p.27Chapter 2.2.3 --- Heterogeneous B*-Trees for Analog Placement with Symmetry and Regularity Considerations --- p.28Chapter 2.3 --- Summary --- p.31Chapter 3 --- Common-Centroid Analog Placement --- p.32Chapter 3.1 --- Problem Formulation --- p.33Chapter 3.2 --- Overview of Our Work --- p.35Chapter 3.3 --- Handling Common Centroid Constraints in Different Devices --- p.37Chapter 3.3.1 --- Common Centroid Placement of Resistors --- p.38Chapter 3.3.2 --- Common Centroid Placement of Transistors --- p.44Chapter 3.3.3 --- Common Centroid Placement of Capacitors --- p.47Chapter 3.4 --- Congestion Estimation and Layout Expansion --- p.50Chapter 3.4.1 --- Blockage-Aware Congestion Estimation --- p.51Chapter 3.4.2 --- Layout Expansion --- p.56Chapter 3.5 --- Simulated Annealing --- p.59Chapter 3.5.1 --- Types of Moves --- p.59Chapter 3.5.2 --- Handling Devices in Symmetry Group --- p.59Chapter 3.5.3 --- Cost Function of Simulated Annealing --- p.61Chapter 3.6 --- Summary --- p.62Chapter 4 --- Experimental Results and Monte-Carlo Simulations --- p.64Chapter 4.1 --- Study of Congestion-driven Layout Expansion --- p.64Chapter 4.2 --- Monte Carlo Simulations --- p.70Chapter 4.2.1 --- Devices Modeling --- p.70Chapter 4.2.2 --- Study of Layouts with and without Symmetry Groups --- p.71Chapter 4.2.3 --- Study of Layouts with and without Self-Symmetry Devices --- p.73Chapter 4.2.4 --- Study of Layouts with Different Number of Symmetry Groups --- p.74Chapter 4.2.5 --- Study of Large and Small Size Capacitors Array --- p.76Chapter 4.3 --- Comparison of Automatic and Manual Layouts using Monte Carlo Simulations --- p.79Chapter 5 --- Conclusion --- p.86Bibliography --- p.8
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